📝 : add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,43 @@
+# CONTRIBUTING
+
+## Releasing a new version
+
+### Creating a release branch
+
+New versions are released using Git Flow release branches.
+
+When releasing a new version, create a branch using the version number to be released.
+
+```bash
+git checkout -b release/1.3.0
+```
+
+### Bump the version number
+
+Change the version number in the `pom.xml` file.
+
+### Generating the CHANGELOG.md
+
+We use `gitmoji-changelog` to generate the `CHANGELOG.md` file.
+
+The `CHANGELOG.md` should be generated just after bumping the version number in the `pom.xml` file.
+
+```bash
+# install gitmoji-changelog
+npm install -g gitmoji-changelog
+
+# generate the changelog
+gitmoji-changelog --preset maven
+```
+
+### Commit & PR
+
+Commit those changes, and open a pull-request for the release-branch.
+
+The commit message should be like `:bookmark: : release 1.3.0`.
+
+### Github Release and Tag
+
+When the PR is merged, create a Github Release, which points on the previous commit, and add the content of the `CHANGELOG.md` to the release.
+
+